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Bioenergetics
Published in Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan, Strength and Conditioning in Sports, 2023
Michael H. Stone, Timothy J. Suchomel, W. Guy Hornsby, John P. Wagle, Aaron J. Cunanan
Investigators have addressed the effects of weight training on subsequent aerobic exercise. Crawford et al. (63) suggest that resistance training has minor effects on subsequent aerobic (treadmill) exercise. However, in that study, only a few sets of one isokinetic leg extension were used, resulting in a very low training volume. Using a routine consisting of nine upper and lower-body exercises with a much larger training volume, Baily et al. (13) found that weight training exercise can alter the typical rate-pressure product response and the heart rate–VO2 relationship. Running economy has been shown to be negatively altered by weight training consisting of a moderate-high volume (215). Interestingly, some evidence suggests that knee extension resistance exercise at 40, 60, and 80% 1RM induces an increased VO2 in non-exercised muscle (forearm flexors) that can persist several minutes after aerobic exercise (206). While not definitive, these studies suggest that the volume of weight training may influence physiological and performance sequelae related to recovery. For various reasons during a daily training routine, many athletes complete a strength-training session first and then move to a different type of conditioning exercise such as a running session, or vice versa. Often, only a few minutes separate these training sessions. Unfortunately, information is lacking with regard to the metabolic efficacy of this type of training routine.
Triathlon
Published in R. C. Richard Davison, Paul M. Smith, James Hopker, Michael J. Price, Florentina Hettinga, Garry Tew, Lindsay Bottoms, Sport and Exercise Physiology Testing Guidelines: Volume I – Sport Testing, 2022
As with aerobic capacity, the efficiency of movement is another important performance determinant (Joyner and Coyle, 2008). When running, this is commonly denoted as running economy, the oxygen cost of a certain speed (ml∙kg−1∙km−1) (see Chapter 4.1 on running). This can be calculated during a step incremental test, as described earlier. It has been shown that the oxygen cost of a set speed is, on average, 2.5 ± 1.5% greater when performed after a cycling bout indicative of standard distance triathlon races compared to when fresh (du Plessis et al., 2020). Thus, practitioners may wish to determine the magnitude of this change in individual athletes as part of their testing battery for greater race specificity.
Substantive Issues in Running
Published in Christopher L. Vaughan, Biomechanics of Sport, 2020
Carol A. Putnam, John W. Kozey
If minimization of oxygen consumption is a crucial performance criteria for running and one assumes that with practice runners adopt an economical running pattern, then forcing a change in certain aspects of a runner’s style should have a predictable effect on running economy. It has been shown that if well-trained runners are forced to alter stride lengths while running at a constant speed (3.8 m/sec) energy costs will change.66 Runners tend naturally to adopt a stride length which is within 4.2 cm of the stride length at which energy cost is minimized.66 However, it is questionable how critical stride length is to running economy. Fairly large variations in stride length result in comparatively small changes in oxygen consumption, and day-to-day variations in stride lengths have not been shown to account for day-to-day variations in running economy.67
Intra- and inter- session reliability of a new method for evaluating toes flexor strength: preliminary study
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
J. Rossi, T. Besson, D. Poncet, G. Y. Millet, C. Y .M. Morio
Running economy is a key determinant of performance in running (Millet et al. 2012) and may be affected by several biomechanical factors (e.g., stiffness) as well as equipment (e.g., shoe mass, cushioning) (Roy and Stefanyshyn 2006). Several studies have recently highlighted that the longitudinal bending stiffness of the shoes is associated with a decrease in running energy cost (Madden et al. 2016). More specifically, McLeod et al. (2020) have reported that shoe construction needs to be personalised in regard to longitudinal bending stiffness when running economy is valued. Consequently, the ability to measure foot muscle strength and particularly at the metatarsophalangeal (MTP) joint is necessary for researchers and shoe companies. Previous studies have used a variety of methods to measure the strength of intrinsic foot muscles (Ridge et al. 2017). The main limitation of existing methods is the positioning of the toes during the strength testing in relation to their position during the walking or running stance phase. Consequently, the aim of this study was to evaluate the intra- and inter- session reliability of a new method evaluating toe flexors.
Does shoe heel-to-toe drop have an influence on performance in downhill trail running?
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
Thomas Defer, Robin Juillaguet, Marlène Giandolini, Sebastien Pavailler, Nicolas Horvais, Johan Cassirame, Gregory Doucende
Therefore, runners were faster with D4 than with D8. This result is explained by a modification of FSP from rear/midfoot strike to forefoot strike dominance. Furthermore, %FFS was higher with D4 than with D8 and there is a relationship between %FFS and performance (Figure 2). Our results are emphasizing with Juillaguet et al. (2018) which suggest that an alteration of biomechanical factors will increase downhill performance. In accordance with this findings, lower drop shoes could also permit improvement of running economy as suggested by Vercruyssen et al. 2016. This result is also described by Di Michele and Merni (2014) who highlighted that higher %FFS is related to lower ground time contact, leading to better adaptations for trail-runners on specific and unpredictable tracks.
Effects of electrolyzed hydrogen water ingestion during endurance exercise in a heated environment on body fluid balance and exercise performance
Published in Temperature, 2020
Hiroto Ito, Shigeru Kabayma, Kazushige Goto
Endurance exercise performance was assessed using the TTE during an incremental pedaling test following 60 min of endurance exercise. We hypothesized that ingesting EHW would prolong the TTE due to altered exercise-induced plasma volume loss. However, EHW ingestion did not affect the TTE during the incremental pedaling test. The energy expenditure during 60 min of continuous pedaling was significantly lower in the EHW trial. Theoretically, lower energy expenditure during submaximal endurance exercise would spare muscle glycogen and decrease cardiovascular strain, leading to improved exercise performance during the latter phase of the prolonged exercise [21]. However, the lower energy expenditure during 60 min of continuous exercise did not extend the TTE during the subsequent exercise, which lasted about 5 min. According to Jeukendrup et al. [21], saving 1% of the energy cost during submaximal cycling exercise improves performance during a 40 km cycling time trial [19]. Therefore, a potential reason for the lack of an apparent effect of the lower energy expenditure may be the exercise duration and situation. Furthermore, several studies have investigated the energy expenditure or energy cost during endurance exercise in real situations and have analyzed the correlation between exercise economy and performance variables (e.g., finishing time of competition) [22]. Cycling (running) economy is traditionally considered an important determinant of endurance exercise performance, although this has not been sufficiently confirmed in a laboratory setting [23]. Therefore, further determination on sports fields is required to draw robust conclusions.